The optimal reaction conditions and catalyst for the synthesis of high molecular weight polystyrene with a desired molecular weight range of 100,000-500,000 g/mol from styrene monomer can be achieved through anionic polymerization.1. Catalyst: Anionic polymerization is initiated by strong nucleophiles, such as organolithium compounds e.g., n-butyllithium, sec-butyllithium or alkali metal alkoxides e.g., potassium tert-butoxide .2. Reaction conditions: a. Temperature: Anionic polymerization is typically carried out at low temperatures 0-40C to minimize side reactions and ensure better control over the molecular weight distribution. b. Solvent: The reaction is usually performed in an inert, aprotic solvent, such as tetrahydrofuran THF , dimethyl sulfoxide DMSO , or toluene. c. Monomer concentration: A high monomer concentration can help achieve the desired high molecular weight. The monomer-to-initiator ratio should be carefully controlled to obtain the desired molecular weight. d. Inhibitor removal: Styrene monomer typically contains inhibitors e.g., tert-butylcatechol to prevent spontaneous polymerization. These inhibitors must be removed before the polymerization process, for example, by passing the monomer through a column filled with activated alumina or using vacuum distillation.3. Reaction control: To achieve the desired molecular weight range, the reaction should be stopped at the appropriate time. This can be done by adding a terminating agent, such as methanol or water, which reacts with the active chain ends and terminates the polymerization.4. Purification: After the reaction is complete, the high molecular weight polystyrene can be isolated by precipitation in a non-solvent e.g., methanol and then dried under vacuum.By carefully controlling the reaction conditions and using an appropriate catalyst, it is possible to synthesize high molecular weight polystyrene with a desired molecular weight range of 100,000-500,000 g/mol from styrene monomer.